## Fluids

#### Modeling Internal Fan

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• elthamer
Subscriber
I have a simple non-ventilated enclosure where inside this closed box (the fluid domain) there is fan which is used to circulate the air to cool an object generating heat. But since the fan is pulling the air from inside this box it doesn?t make sense that I define the temperature of the inlet & opening of the fan in the boundary condition since that temperature is dependent on the solution (air temperature inside the enclosure).nI was wondering if there is a tutorial available that covers solution dependent expressions for fan cooling simulation. Or a way of coupling the inlet temperature to the air temperature from the solution.nHere?s a brief description of my model:n? The volume where the fan occupied was cut out. Here, there are: walls, one face for fan intake and one face for fan opening.n? For the ?opening? side (back of the fan) I am using: 0 Pa pressure with a guess value of what the air temperature going in is (this needs to be corrected since this should be solution dependent)n? For the inlet side (flow into the fluid domain), I am using: mass flow rate (toward the fluid domain) with a guess value of what the air temperature going out is (this also needs to be corrected since this should be solution dependent)n? For the remaining faces (wall sides), I assigned a constant heat flux to represent the heat dissipation of the fan.nI am using CFX.nThanks,nThamern
• YasserSelima
Subscriber
Fluent has a fan model where you can write your own function to add the pressure drop, swirl and radial velocity. Not sure if it is available for CFXn
• elthamer
Subscriber
Thanks Yasser for your response. I learned that the best way to model a fan (for my situation) is to use a momentum source term. This video below does a good job in explaining how to do it in CFX if anyone else is interested. It also takes into account the fan curve.nnn